Thermal protection composite material and method for manufacturing the same

Abstract

The present application relates to the technical field of functional materials, and particularly relates to a thermal protection composite material and a preparation method thereof, the preparation method comprising the following steps: S1, hollow SiO2 is modified by hydrolysis using a silane coupling agent; S2, the modified hollow SiO2 and the silane coupling agent are added to a silicone resin and uniformly dispersed to obtain a modified silicone resin; S3, the modified hollow SiO2 is grafted to the surface of glass fiber cloth to obtain hollow SiO2 grafted glass fiber cloth; and S4, the modified silicone resin is coated on the surface of an aluminum foil, and the hollow SiO2 grafted glass fiber cloth is laminated on the modified silicone resin and dried to obtain the thermal protection composite material. The thermal protection composite material has high reflection and high thermal protection performance, and has high peeling strength.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, and in particular to a thermal protective composite material and its preparation method. Background Technology

[0002] Thermally protective composite materials are materials specifically designed to protect structures or equipment from high-temperature environments. These composites are widely used in aerospace, automotive, military, and industrial fields. Key characteristics include high heat resistance, excellent thermal insulation, and thermal stability.

[0003] Existing thermal protection composite materials are mainly made of aramid fiber as the main component, supplemented by various high-temperature resistant materials. This type of material is not only complex to manufacture, but also has a high cost, which is not conducive to large-scale production by enterprises.

[0004] Aluminum foil and fiberglass composite material is a simple and low-cost material. It uses one or more thermoplastic materials such as polyester to bond aluminum foil and fiberglass fabric through hot pressing or adhesive. Although thermoplastic materials have good bonding effect, their high temperature resistance is poor. They generally melt at around 250°C and are not suitable for high-temperature applications. Their heat protection performance and peel strength are also insufficient. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of insufficient thermal protection performance and peel strength of aluminum foil-glass fiber composite materials described in the background art. Here, a thermal protection composite material and its preparation method are proposed. The thermal protection composite material uses hollow SiO2 modified organosilicon resin as an adhesive to bond aluminum foil and glass fiber fabric, thereby improving the thermal protection performance and peel strength of the aluminum foil-glass fiber composite material.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a method for preparing a thermal protection composite material, the preparation method comprising the following steps:

[0007] Preparation of S1 modified hollow SiO2

[0008] Hollow SiO2 was mixed with anhydrous ethanol to obtain a first mixture, which was then set aside.

[0009] The silane coupling agent was mixed with water to obtain a second mixture, which was then cooled to room temperature for later use.

[0010] The first and second mixtures are mixed and refluxed at 60-80℃ for 2-4 hours. The mixtures are washed and filtered until the filtrate is clear and transparent. The filter cake is then vacuum dried at 50-80℃ to obtain modified hollow SiO2.

[0011] S2. Preparation of modified organosilicon resin

[0012] The modified hollow SiO2 and silane coupling agent were added to the organosilicon resin and dispersed evenly to obtain the modified organosilicon resin.

[0013] Preparation of S3, hollow SiO2 grafted glass fiber cloth

[0014] Hollow SiO2 was added to the ethanol solution and dispersed evenly to obtain a third mixture, which was then set aside.

[0015] Mix the silane coupling agent with the ethanol solution and stir continuously for 15 minutes to obtain the fourth mixture, which is then set aside.

[0016] The fiberglass cloth was immersed in the third mixture for 15 minutes, removed and dried, then immersed in the fourth mixture for 15 minutes, removed and dried to obtain hollow SiO2 grafted fiberglass cloth.

[0017] S4. Preparation of thermal protection composite materials

[0018] Modified silicone resin was coated onto the surface of aluminum foil, and hollow SiO2-grafted fiberglass cloth was pressed onto the modified silicone resin and dried to obtain a thermal protection composite material.

[0019] In the above technical solution, the reaction principle of step S1 is shown in equations (1) and (2) below:

[0020]

[0021] First, silane coupling agent is used for hydrolysis, and then hollow SiO2 is modified to reduce the number of hydroxyl groups on the surface of hollow SiO2, thereby reducing the aggregation of hollow SiO2 and enabling it to be uniformly dispersed in solution; the reaction principle of step S3 is shown in equations (3) and (1) below:

[0022]

[0023] The silane coupling agent is hydrolyzed to modify hollow SiO2. The modified hollow SiO2 is then grafted onto the surface of glass fiber, thereby increasing the surface roughness of the glass fiber. This enhances the mechanical interlocking force between the interface when bonding aluminum foil and glass fiber, thus improving the overall peel strength of the material. The modified silicone resin prepared in step S2, due to the good thermal insulation properties of hollow SiO2 itself, and taking advantage of its hollow and lightweight characteristics, will spontaneously form a dense hollow SiO2 film during the material curing process. This film can effectively reflect the heat radiation that penetrates the outer aluminum foil, further improving the thermal protection performance of the material itself.

[0024] Preferably, in step S1, the mass-to-volume ratio of hollow SiO2 to anhydrous ethanol is 1:30 (g / mL), the volume ratio of silane coupling agent to water is 1:(1-3), and the mass-to-volume ratio of hollow SiO2 to silane coupling agent is 1:5 (g / mL).

[0025] Preferably, in step S2, the modified hollow SiO2 in the modified organosilicon resin has a mass fraction of 2%-8%, and the silane coupling agent in the modified organosilicon resin has a mass fraction of 2%. Further, the mass fraction of the modified hollow SiO2 in the modified organosilicon resin is preferably 2%.

[0026] Preferably, in step S3, the mass fraction of hollow SiO2 in the third mixture is 0.5%-2%, and the mass fraction of silane coupling agent in the fourth mixture is 0.5%-2%. Further, the mass fraction of hollow SiO2 in the third mixture is 1%, and the mass fraction of silane coupling agent in the fourth mixture is 1%.

[0027] Preferably, in step S4, the drying process specifically involves drying at 80°C for 40 minutes, then at 120°C for 40 minutes, and finally at 160°C for 40 minutes.

[0028] Preferably, in steps S2 and S3, the dispersion specifically involves: first, continuous stirring for 0.5 hours, followed by ultrasonic oscillation for 0.5 hours, wherein the stirring rate is 180-500 rpm and the ultrasonic frequency is 28-40 kHz.

[0029] Preferably, in step S3, the volume fraction of the ethanol solution is 75%.

[0030] Preferably, the silane coupling agent is KH550.

[0031] A thermal protection composite material prepared by the method described above, the thermal protection composite material comprising a first aluminum foil layer, a first modified silicone resin layer and a first glass fiber layer arranged sequentially.

[0032] Preferably, the thermal protection composite material further includes a second aluminum foil layer, a second modified silicone resin layer, and a second glass fiber layer disposed sequentially, wherein the second glass fiber layer is in contact with the first glass fiber layer.

[0033] The beneficial effects of this invention are:

[0034] 1. This invention uses glass fiber as the base fabric and modified organosilicon resin with modified hollow SiO2 to bond aluminum foil. The process is simple and the cost is low.

[0035] 2. This invention modifies hollow SiO2 and uses the modified hollow SiO2 to modify organosilicon resin, which effectively improves the thixotropic properties of organosilicon resin and enhances its thermal protection performance.

[0036] 3. This invention grafts hollow SiO2 onto fiberglass cloth, which effectively increases the roughness of the fiberglass cloth, thereby improving the peel strength of the thermal protection composite material.

[0037] 4. This invention utilizes the hollow and lightweight properties of hollow SiO2. During its curing and drying process, a dense hollow SiO2 film will spontaneously form upwards. Combined with the self-generated hollow characteristics of hollow SiO2, the overall thermal protection performance of the material is further improved. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the thermal protection composite material of the present invention;

[0039] Figure 2 This is a schematic diagram illustrating the heating principle of one embodiment of the thermal protection composite material of the present invention.

[0040] Figure 3 The thermal protection performance diagrams are shown for the thermal protection composite materials prepared in Examples 1-4 and Comparative Example 1.

[0041] Figure 4 The reflectance diagrams are of the thermal protective composite materials prepared in Examples 1-4 and Comparative Example 1.

[0042] Figure 5 Peel strength diagrams of the thermal protective composite materials prepared in Examples 1-4 and Comparative Example 1;

[0043] Figure 6 The images show the radiation heat penetration resistance of the thermal protection composite materials prepared in Examples 1-4 and Comparative Example 1. Detailed Implementation

[0044] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] The present invention will now be further illustrated with specific examples. The following embodiments are only for explaining the present invention and do not constitute a limitation thereof. The test samples and test procedures used in the following embodiments include the following (if the specific experimental conditions are not specified in the embodiments, they are usually performed according to conventional conditions or the conditions recommended by the reagent company; the reagents, consumables, etc. used in the following embodiments can be obtained commercially unless otherwise specified).

[0047] The raw materials used in this invention are: hollow SiO2 purchased from Gongyi Fanrui Yihui Composite Materials Co., Ltd., with a particle size of 21 micrometers or 46 micrometers; and organosilicon resin purchased from Hubei Longsheng Sihai New Materials Co., Ltd.

[0048] Example 1

[0049] A method for preparing a thermally protective composite material, the specific steps of which are as follows:

[0050] Preparation of S1 modified hollow SiO2

[0051] Take 5g of hollow SiO2 and 150mL of anhydrous ethanol, mix them and add them to a three-necked flask. Stir to disperse the hollow SiO2 evenly in the anhydrous ethanol to obtain the first mixture for later use.

[0052] Take 25 mL of silane coupling agent KH550 and mix it evenly with 50 mL of water. Stir continuously to allow the silane coupling agent KH550 to be fully hydrolyzed until it is cooled to room temperature to obtain a second mixture for later use.

[0053] The first mixture and the second mixture were mixed and stirred thoroughly. The mixture was then refluxed at 70°C for 3 hours in a constant temperature magnetic stirrer. After the reaction was completed, the mixture was repeatedly washed and filtered with anhydrous ethanol until the filtrate was clear and transparent. The filter cake was then dried in a vacuum drying oven at 70°C to obtain modified hollow SiO2.

[0054] S2. Preparation of modified organosilicon resin

[0055] Modified hollow SiO2 and silane coupling agent KH550 were added to organosilicon resin, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain modified organosilicon resin. The mass fraction of modified hollow SiO2 was 2%, and the mass fraction of silane coupling agent KH550 was 2%. The high-speed stirring rate was 280 rpm, and the ultrasonic frequency was 40 kHz.

[0056] Preparation of S3, hollow SiO2 grafted glass fiber cloth

[0057] Hollow SiO2 was added to a 75% (v / v) ethanol solution, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain a third mixture for later use.

[0058] Add silane coupling agent KH550 to a 75% (v / v) ethanol solution and stir for 15 min to obtain a fourth mixture for later use.

[0059] The third mixture contains 0.5% hollow SiO2 by mass, and the fourth mixture contains 0.5% silane coupling agent KH550 by mass.

[0060] S4. Preparation of thermal protection composite materials

[0061] Modified silicone resin was uniformly coated onto aluminum foil, and then hollow SiO2-grafted fiberglass cloth was pressed onto the modified silicone resin layer. Excess resin was extruded using a pressure roller. The mixture was first baked at 80°C for 40 minutes, then at 120°C for 40 minutes, and finally at 160°C for 40 minutes to obtain a thermal protection composite material.

[0062] Example 2

[0063] A method for preparing a thermally protective composite material, the specific steps of which are as follows:

[0064] Preparation of S1 modified hollow SiO2

[0065] Take 5g of hollow SiO2 and 150mL of anhydrous ethanol, mix them and add them to a three-necked flask. Stir to disperse the hollow SiO2 evenly in the anhydrous ethanol to obtain the first mixture for later use.

[0066] Take 25 mL of silane coupling agent KH550 and mix it evenly with 25 mL of water. Stir continuously to allow the silane coupling agent KH550 to be fully hydrolyzed until it is cooled to room temperature to obtain a second mixture for later use.

[0067] The first mixture and the second mixture were mixed and stirred thoroughly. The mixture was then refluxed at 70°C for 3 hours in a constant temperature magnetic stirrer. After the reaction was completed, the mixture was repeatedly washed and filtered with anhydrous ethanol until the filtrate was clear and transparent. The filter cake was then dried in a vacuum drying oven at 70°C to obtain modified hollow SiO2.

[0068] S2. Preparation of modified organosilicon resin

[0069] Modified hollow SiO2 and silane coupling agent KH550 were added to organosilicon resin, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain modified organosilicon resin. The mass fraction of modified hollow SiO2 was 4%, and the mass fraction of silane coupling agent KH550 was 2%. The high-speed stirring rate was 280 rpm, and the ultrasonic frequency was 40 kHz.

[0070] Preparation of S3, hollow SiO2 grafted glass fiber cloth

[0071] Hollow SiO2 was added to a 75% (v / v) ethanol solution, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain a third mixture for later use.

[0072] Add silane coupling agent KH550 to a 75% (v / v) ethanol solution and stir for 15 min to obtain a fourth mixture for later use.

[0073] The third mixture contains 1% hollow SiO2 by mass, and the fourth mixture contains 1% silane coupling agent KH550 by mass.

[0074] S4. Preparation of thermal protection composite materials

[0075] Modified silicone resin was uniformly coated onto aluminum foil, and then hollow SiO2-grafted fiberglass cloth was pressed onto the modified silicone resin layer. Excess resin was extruded using a pressure roller. The mixture was first baked at 80°C for 40 minutes, then at 120°C for 40 minutes, and finally at 160°C for 40 minutes to obtain a thermal protection composite material.

[0076] Example 3

[0077] A method for preparing a thermally protective composite material, the specific steps of which are as follows:

[0078] Preparation of S1 modified hollow SiO2

[0079] Take 5g of hollow SiO2 and 150mL of anhydrous ethanol, mix them and add them to a three-necked flask. Stir to disperse the hollow SiO2 evenly in the anhydrous ethanol to obtain the first mixture for later use.

[0080] Take 25 mL of silane coupling agent KH550 and mix it evenly with 75 mL of water. Stir continuously to allow the silane coupling agent KH550 to be fully hydrolyzed until it is cooled to room temperature to obtain a second mixture for later use.

[0081] The first mixture and the second mixture were mixed and stirred thoroughly. The mixture was then refluxed at 70°C for 3 hours in a constant temperature magnetic stirrer. After the reaction was completed, the mixture was repeatedly washed and filtered with anhydrous ethanol until the filtrate was clear and transparent. The filter cake was then dried in a vacuum drying oven at 70°C to obtain modified hollow SiO2.

[0082] S2. Preparation of modified organosilicon resin

[0083] Modified hollow SiO2 and silane coupling agent KH550 were added to organosilicon resin, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain modified organosilicon resin. The mass fraction of modified hollow SiO2 was 6%, and the mass fraction of silane coupling agent KH550 was 2%. The high-speed stirring rate was 280 rpm, and the ultrasonic frequency was 40 kHz.

[0084] Preparation of S3, hollow SiO2 grafted glass fiber cloth

[0085] Hollow SiO2 was added to a 75% (v / v) ethanol solution, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain a third mixture for later use.

[0086] Add silane coupling agent KH550 to a 75% (v / v) ethanol solution and stir for 15 min to obtain a fourth mixture for later use.

[0087] The third mixture contains 2% hollow SiO2 by mass, and the fourth mixture contains 2% silane coupling agent KH550 by mass.

[0088] S4. Preparation of thermal protection composite materials

[0089] Modified silicone resin was uniformly coated onto aluminum foil, and then hollow SiO2-grafted fiberglass cloth was pressed onto the modified silicone resin layer. Excess resin was extruded using a pressure roller. The mixture was first baked at 80°C for 40 minutes, then at 120°C for 40 minutes, and finally at 160°C for 40 minutes to obtain a thermal protection composite material.

[0090] Example 4

[0091] A method for preparing a thermally protective composite material, the specific steps of which are as follows:

[0092] Preparation of S1 modified hollow SiO2

[0093] Take 5g of hollow SiO2 and 150mL of anhydrous ethanol, mix them and add them to a three-necked flask. Stir to disperse the hollow SiO2 evenly in the anhydrous ethanol to obtain the first mixture for later use.

[0094] Take 25 mL of silane coupling agent KH550 and mix it evenly with 75 mL of water. Stir continuously to allow the silane coupling agent KH550 to be fully hydrolyzed until it is cooled to room temperature to obtain a second mixture for later use.

[0095] The first mixture and the second mixture were mixed and stirred thoroughly. The mixture was then refluxed at 70°C for 3 hours in a constant temperature magnetic stirrer. After the reaction was completed, the mixture was repeatedly washed and filtered with anhydrous ethanol until the filtrate was clear and transparent. The filter cake was then dried in a vacuum drying oven at 70°C to obtain modified hollow SiO2.

[0096] S2. Preparation of modified organosilicon resin

[0097] Modified hollow SiO2 and silane coupling agent KH550 were added to organosilicon resin, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain modified organosilicon resin. The mass fraction of modified hollow SiO2 was 8%, and the mass fraction of silane coupling agent KH550 was 2%. The high-speed stirring rate was 280 rpm, and the ultrasonic frequency was 40 kHz.

[0098] Preparation of S3, hollow SiO2 grafted glass fiber cloth

[0099] Hollow SiO2 was added to a 75% (v / v) ethanol solution, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain a third mixture for later use.

[0100] Add silane coupling agent KH550 to a 75% (v / v) ethanol solution and stir for 15 min to obtain a fourth mixture for later use.

[0101] The third mixture contains 2% hollow SiO2 by mass, and the fourth mixture contains 2% silane coupling agent KH550 by mass.

[0102] S4. Preparation of thermal protection composite materials

[0103] Modified silicone resin was uniformly coated onto aluminum foil, and then hollow SiO2-grafted fiberglass cloth was pressed onto the modified silicone resin layer. Excess resin was extruded using a pressure roller. The mixture was first baked at 80°C for 40 minutes, then at 120°C for 40 minutes, and finally at 160°C for 40 minutes to obtain a thermal protection composite material.

[0104] Comparative Example 1

[0105] A method for preparing a thermally protective composite material, the specific steps of which are as follows:

[0106] Preparation of S1, hollow SiO2 grafted glass fiber cloth

[0107] Hollow SiO2 was added to a 75% (v / v) ethanol solution, stirred at high speed for 30 min, and ultrasonically vibrated for 30 min to obtain a third mixture for later use.

[0108] Add silane coupling agent KH550 to a 75% (v / v) ethanol solution and stir for 15 min to obtain a fourth mixture for later use.

[0109] The third mixture contains 2% hollow SiO2 by mass, and the fourth mixture contains 2% silane coupling agent KH550 by mass; the high-speed stirring rate is 280 rpm, and the ultrasonic frequency is 40 kHz.

[0110] S2, Preparation of thermal protection composite materials

[0111] Silicone resin is uniformly coated onto aluminum foil, and then hollow SiO2-grafted fiberglass cloth is pressed onto the silicone resin layer. Excess resin is extruded using a pressure roller. The material is first baked at 80°C for 40 minutes, then at 120°C for 40 minutes, and finally at 160°C for 40 minutes to obtain a heat-protective composite material.

[0112] The thermal protective composite materials prepared in Examples 1-4 have the following structures: Figure 1 As shown, the thermal protection composite material is composed of a first aluminum foil layer 1, a first modified silicone resin layer 2 and a first glass fiber layer 3 from top to bottom. In the first modified silicone resin layer, due to the lightweight nature of hollow SiO2, a dense hollow SiO2 layer 4 will spontaneously form upwards during the drying and curing process in step S4.

[0113] In another embodiment, two thermal protection composite materials can be stacked to form a composite material with better thermal protection performance. Specifically, from top to bottom, it consists of a first aluminum foil layer 1, a first modified silicone resin layer 2, a first glass fiber layer 3, a second glass fiber layer, a second modified silicone resin layer, and a second aluminum foil layer. The heating principle diagram of this thermal protection composite material is shown below. Figure 2 As shown, the first aluminum foil layer near the fire source reflects most of the heat radiation once, and the part of the heat radiation that passes through is reflected a second time. A small part of the heat radiation passes through the second aluminum foil layer. The aluminum foil layer can reflect 90% of the heat radiation. The heat radiation that passes through the aluminum foil is further reflected by the hollow SiO2 layer floating on the top of the first modified silicone resin layer. A small amount of the remaining heat radiation can pass through the second aluminum foil layer.

[0114] The performance of the thermal protective composite materials prepared in Examples 1-4 and Comparative Example 1 was tested.

[0115] Thermal Protection Performance Testing Method: The thermal protection performance tester for thermal protection materials simulates the thermal protection capability of materials under the combined effects of radiant and convective heat in a real fire environment. The testing instrument is a TPP (Thermal Protective Performance Tester). The instrument design conforms to testing standards such as NFPA 2112—2007 "Standard for Fire-Resistant Clothing for Industrial Personnel". The test uses a heat flux density of 84±2 kW / m³. 2 The fabric was placed horizontally on the sample holder using a mixed radiation-convection heat source. During the test, the temperature rise curve on the back of the fabric was measured using a copper sheet heat flow meter, and compared with the Stoll curve to obtain the time t required for secondary burns. Then, the TPP value of the fabric was calculated according to equation (1-1).

[0116] TPP=q×t (1-1)

[0117] Where: TPP – Comprehensive thermal protection performance value of the fabric, kw·s / m 2 ;

[0118] q – Actual heat flow, kw / m³ 2 ;

[0119] t – Time required for a second-degree burn, in seconds.

[0120] Reflectance testing method: Ultraviolet-Visible-Near Infrared Spectrophotometry.

[0121] Peel strength test method: The sample test was conducted according to GB / T 2792—2014 "Test method for peel strength of adhesive tape". A 20cm×20cm double-layer glass fiber fabric sandwiched with aluminum foil was prepared as shown in the figure. An aluminum foil was sandwiched between two pieces of glass fiber fabric and bonded with modified adhesive. After the prepared sample was dried and cured, it was cut into strips with a width of 25mm to test the peel performance of the aluminum foil glass fiber fabric composite fabric.

[0122] Radiation heat penetration resistance test method: The test method is similar to the equipment used in the thermal protection performance test method, the difference being that the burning effect of heat convection is eliminated. Radiation heat penetration resistance performance is tested according to the test standard GA634-2015 "Firefighter Thermal Protective Clothing", measuring the temperature rise of the thermal protection material after 1 minute of radiation.

[0123] The thermal protection performance of thermal protective composite materials, such as Figure 3 As shown, the addition of modified hollow SiO2 can effectively enhance the thermal protection performance of the material, and the thermal protection performance of the thermal protection composite material increases linearly with the increase of the mass fraction of modified hollow SiO2 in the modified organosilicon resin.

[0124] The reflectivity of thermal protective composite materials, such as Figure 4 As shown, it can be seen that the reflectivity of the thermal protection composite material increases with the increase of the mass fraction of modified hollow SiO2 in the modified silicone resin. This may be because the film layer formed by the modified hollow SiO2 on the top of the modified silicone resin is more dense.

[0125] Peel strength of thermal protective composite materials, such as Figure 5 As shown, with the increase of the mass fraction of modified hollow SiO2 in the modified silicone resin, the peel strength of the thermal protection composite material first increases and then decreases, reaching its maximum value when the mass fraction of hollow SiO2 is 2%. This is because the viscosity of the silicone resin adhesive without added hollow SiO2 is too low, allowing it to directly penetrate from the glass fiber, leaving less adhesive residue between the aluminum foil and the glass fiber, resulting in poor adhesion. The silicone resin with added 2% hollow SiO2 penetrates into the glass fiber fabric during bonding. Due to the increased viscosity, some adhesive penetrates into the glass fiber fabric, while some adheres to the fabric surface, achieving a good mechanical bonding effect and thus improving the adhesion performance between the aluminum foil and the glass fiber fabric. When the mass fraction of hollow SiO2 added reaches 4%, 6%, and 8%, the viscosity of the silicone resin adhesive gradually increases. The higher the viscosity, the worse the fluidity, and the less silicone resin adhesive penetrates into the glass fiber fabric. It can only stay on the surface of the glass fiber fabric. Therefore, the higher the viscosity, the lower the peel strength gradually becomes.

[0126] The radiation heat penetration resistance of thermal protection composite materials, such as Figure 6 As shown, with the increase of the mass fraction of modified hollow SiO2 in the modified silicone resin, the radiation heat penetration resistance of the thermal protection composite material is also enhanced.

[0127] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0128] The present invention provides a detailed description of a thermal protective composite material and its preparation method. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of these examples are merely for the purpose of helping to understand the method and core ideas of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a thermally protective composite material, characterized in that: The preparation method includes the following steps: Preparation of S1 and modified hollow SiO2 Hollow SiO2 was mixed with anhydrous ethanol to obtain a first mixture, which was then set aside. The silane coupling agent was mixed with water to obtain a second mixture, which was then cooled to room temperature for later use. The first and second mixtures are mixed and refluxed at 60-80℃ for 2-4 hours. The mixtures are washed and filtered until the filtrate is clear and transparent. The filter cake is then vacuum dried at 50-80℃ to obtain modified hollow SiO2. S2. Preparation of modified organosilicon resin The modified hollow SiO2 and silane coupling agent were added to the organosilicon resin and dispersed evenly to obtain the modified organosilicon resin. Preparation of S3, hollow SiO2 grafted glass fiber cloth Hollow SiO2 was added to the ethanol solution and dispersed evenly to obtain a third mixture, which was then set aside. Mix the silane coupling agent with the ethanol solution and stir continuously for 15 minutes to obtain the fourth mixture, which is then set aside. The fiberglass cloth was immersed in the third mixture for 15 minutes, removed and dried, then immersed in the fourth mixture for 15 minutes, removed and dried to obtain hollow SiO2 grafted fiberglass cloth. S4. Preparation of thermal protection composite materials Modified silicone resin was coated on the surface of aluminum foil, hollow SiO2-grafted fiberglass cloth was pressed onto the modified silicone resin, and then dried to obtain a thermal protection composite material. In steps S2 and S3, the dispersion specifically involves: first, continuous stirring for 0.5 hours, followed by ultrasonic oscillation for 0.5 hours, wherein the stirring rate is 180-500 rpm and the ultrasonic frequency is 28-40 kHz; In step S4, the drying process specifically involves drying at 80°C for 40 minutes, then at 120°C for 40 minutes, and finally at 160°C for 40 minutes.

2. The preparation method according to claim 1, characterized in that: In step S1, the mass-to-volume ratio of hollow SiO2 to anhydrous ethanol is 1:30 (g / mL), the volume ratio of silane coupling agent to water is 1:(1-3), and the mass-to-volume ratio of hollow SiO2 to silane coupling agent is 1:5 (g / mL).

3. The preparation method according to claim 1, characterized in that: In step S2, the modified hollow SiO2 in the modified organosilicon resin has a mass fraction of 2%-8%, and the silane coupling agent in the modified organosilicon resin has a mass fraction of 2%.

4. The preparation method according to claim 1, characterized in that: In step S3, the mass fraction of hollow SiO2 in the third mixture is 0.5%-2%, and the mass fraction of silane coupling agent in the fourth mixture is 0.5%-2%.

5. The preparation method according to claim 1, characterized in that: In step S3, the volume fraction of the ethanol solution is 75%.

6. The preparation method according to claim 1, characterized in that: The silane coupling agent is KH550.

7. A thermal protective composite material prepared by the preparation method according to any one of claims 1-6, characterized in that: The thermal protection composite material includes a first aluminum foil layer (1), a first modified silicone resin layer (2), and a first glass fiber layer (3) arranged sequentially.

8. The thermal protection composite material according to claim 7, characterized in that: The thermal protection composite material further includes a second aluminum foil layer, a second modified silicone resin layer, and a second glass fiber layer arranged sequentially, with the second glass fiber layer in contact with the first glass fiber layer.

Images